Maintenance of railroad track and replacement of railroad ties requires the removal of spikes from the ties to permit separation of the track from the ties and positioning of new ties. Removal of the spikes is also required to permit replacement of worn or damaged rails or replacement of joined rails with continuous lengths of rail welded together.
One of the prior art methods for use in removing the spikes from the ties and tie plates requires the use of a pry bar having a claw on one end, and the spikes are manually pried out of the ties.
Machines have also been constructed for mechanically pulling spikes out of the ties. Such machines commonly include a clamping assembly including a pair of jaws movable toward and away from each other and operable to grip the head of the tie spike. Mechanical means are provided for then lifting the clamping assembly such that the spike is pulled from the tie and tie plate. This means for lifting the clamping assembly can be either a hydraulic cylinder or a mechanical lifting device.
One of the problems with such prior art spike pulling machines is that in many cases two operators are required, one to operate and guide the clamping devices on one side of the rail and another operator to guide the clamping assembly on the other side of the rail. Another problem with the prior art spike pullers is that they are not effective to pull spikes where there is a joint of two rails. The mechanical structure of the joint interfers with the opposed clamping members and prohibits the opposed clamping jaws from gripping the spike head. Commonly, the spikes in the area of each joint must be removed manually using a pry bar.
Another problem with prior art spike puller machines is that the entire machine must be carefully positioned over each spike so that the clamping members are properly aligned on opposite sides of the spikes.
Another problem with the prior art spike pullers is that maintenance of the machines can be expensive. The clamping members or jaws may become worn and replacement is expensive.